From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 12B8A2D12E7 for ; Tue, 12 Aug 2025 16:20:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755015657; cv=none; b=FaiX/vgxEdKqwgNGDCEkY+XoKvjp9MuHUed30dROdOKAhdgaQeeYKeMLw6CGXNmmpATEHrr3tz+e6ywKXmoPVLVwwILg2+5XBELecbYrNV3lqHGkMbCYM++QTBmHCfHnmiDlD4HcfoJh9Fw4vkb3XdaTvHum3N8v8MNvJ4MNNA0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755015657; c=relaxed/simple; bh=p2/88+VxGB7tz9k+ZIXlAUVubdUTwVjhB9Ht42CCnLE=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=rKspJCeMwX+3jCVnHAWYaSjwJVqt5MBcOVqogHEantWlpeBHmKTb8c3IvAPJmUWKw0eAS5CYvAUY0y9nAK2y7JKEuyJrAgs881Y/GLEDrkHslG57EN0uAavX3iGK/GysVfAPyIfz1JgOQysloayV0lf8cp0AxR14lubqzfXiCH4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=x8tNAOeX; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="x8tNAOeX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 77948C4CEF6; Tue, 12 Aug 2025 16:20:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1755015656; bh=p2/88+VxGB7tz9k+ZIXlAUVubdUTwVjhB9Ht42CCnLE=; h=Subject:To:Cc:From:Date:From; b=x8tNAOeXeioRQekJjrh7YzBNmqzLVC5J5Aj3GtS6QuaKkG103kwmoDC9u8ru+Bifl yrwvKL6xhiNERD+3XE3PNwPX4okwsiSWSd5yaxbPbe0s52jy7DgWYCYSQ28Al9N+C/ ry0nZhu2HVEpbPTfcJlImTWQcHHLhwclPKRSGVGg= Subject: FAILED: patch "[PATCH] HID: core: Harden s32ton() against conversion to 0 bits" failed to apply to 5.4-stable tree To: stern@rowland.harvard.edu,bentiss@kernel.org Cc: From: Date: Tue, 12 Aug 2025 18:20:35 +0200 Message-ID: <2025081235-dinghy-spectrum-644a@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x a6b87bfc2ab5bccb7ad953693c85d9062aef3fdd # git commit -s git send-email --to '' --in-reply-to '2025081235-dinghy-spectrum-644a@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From a6b87bfc2ab5bccb7ad953693c85d9062aef3fdd Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Wed, 23 Jul 2025 10:37:04 -0400 Subject: [PATCH] HID: core: Harden s32ton() against conversion to 0 bits Testing by the syzbot fuzzer showed that the HID core gets a shift-out-of-bounds exception when it tries to convert a 32-bit quantity to a 0-bit quantity. Ideally this should never occur, but there are buggy devices and some might have a report field with size set to zero; we shouldn't reject the report or the device just because of that. Instead, harden the s32ton() routine so that it returns a reasonable result instead of crashing when it is called with the number of bits set to 0 -- the same as what snto32() does. Signed-off-by: Alan Stern Reported-by: syzbot+b63d677d63bcac06cf90@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-usb/68753a08.050a0220.33d347.0008.GAE@google.com/ Tested-by: syzbot+b63d677d63bcac06cf90@syzkaller.appspotmail.com Fixes: dde5845a529f ("[PATCH] Generic HID layer - code split") Cc: stable@vger.kernel.org Link: https://patch.msgid.link/613a66cd-4309-4bce-a4f7-2905f9bce0c9@rowland.harvard.edu Signed-off-by: Benjamin Tissoires diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index ef1f79951d9b..f7d4efcae603 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -66,8 +66,12 @@ static s32 snto32(__u32 value, unsigned int n) static u32 s32ton(__s32 value, unsigned int n) { - s32 a = value >> (n - 1); + s32 a; + if (!value || !n) + return 0; + + a = value >> (n - 1); if (a && a != -1) return value < 0 ? 1 << (n - 1) : (1 << (n - 1)) - 1; return value & ((1 << n) - 1);